Showing papers by "Elsebeth Lynge published in 1999"

Work-related Cancer in the Nordic Countries

Abstract: This report presents 20 years' of cancer incidence data by occupational group for the Nordic populations. The study covers the 10 million people aged 25-64 years at the time of the 1970 censuses in Denmark, Finland, Norway, and Sweden, and the 1 million incident cancer cases diagnosed among these people during the subsequent 20 years. The project was undertaken as a cohort study with linkage of individual records based on the personal identification numbers used in all the Nordic countries. In the 1970 censuses, information on occupation for each economically active member of the household was provided in free text in self-administered questionnaires. The data were centrally coded and computerized in the statistical offices. Norway, Sweden, and Finland used the Nordic Classification of Occupations, while Denmark used a national coding scheme. However, all the data could be reclassified into 53 occupational groups and 1 group of economically inactive persons. Person-years at risk were accumulated from 1 January 1971 until the date of emigration, date of death or 31 December 1987 in Denmark, 1989 in Sweden, 1990 in Finland, and 1991 in Norway. The 4 countries all had nationwide registration of incident cancer cases during the entire study period. All incident cancer cases during the individual risk periods were included in the analysis. Despite minor differences between the countries, the International Classification of Diseases, 7th revision, formed the core basis for the diagnostic coding in all 4 countries. For the present study the incident cancer cases have been classified into 35 broad diagnostic groups. The observed number of cancer cases in each group of persons defined by country, gender, and occupation was compared with the expected number calculated from the age-, gender-, and period-specific person-years and the incidence rates for the national population. The result has been presented as a standardized incidence ratio (SIR), defined as the observed number of cases divided by the expected number and multiplied by 100. In the tables of this report, all the SIR values for which the upper limit of the 95% confidence interval is below 100 are printed in green and all those for which the lower limit of the confidence interval is above 100 are printed in red. For all cancers combined, the study showed a wide variation among the men, from an SIR of 79 for farmers to 159 for waiters. The occupations with the highest SIR values also included seamen and workers producing beverages and tobacco. Among the women the SIR values varied from 83 for gardeners to 129 for tobacco workers. Low SIR values were found for farmers and teachers. Outdoor workers such as fishermen and gardeners had the highest risk of lip cancer, while the lowest risk was found among indoor workers such as physicians and artistic workers. Almost all pleural cancers are associated with asbestos exposure. Accordingly, plumbers, welders, mechanics, and seamen were the occupations with the highest risk. There was also an excess risk of pleural cancer in the occupational group of technical, chemical, physical, and biological workers, including, among others, engineers and chemists potentially exposed to asbestos. The wood workers included in the present study had the highest risk of nasal cancer. Most studies of nasal cancer have shown increased risks associated with exposure to wood dust, both for those in furniture making and for those exposed exclusively to soft wood. Nickel refinery workers are also known for their high risk of nasal cancer. In the present study they were included in the occupational group of smelting workers. Lung cancer was the most frequent cancer among men in the present study. Tobacco smoking is the major risk factor for this disease, but occupational exposures also play an important role. Waiters and tobacco workers had the highest risk of lung cancer. Miners and quarry workers also had a high risk of lung cancer, which may be related to

Occupation and bladder cancer in European women.

Abstract: Objectives: We examined the importance of occupational exposures for bladder cancer in women. Methods: We combined data from 11 case-control studies conducted between 1976 and 1996 in six European countries. The pooled data comprised 700 incident female cases and 2425 population or hospital controls, aged 3079 years. Lifetime occupational and smoking history were examined using common coding. Results: Excess risks were found in only a few of the occupations previously identified at high risk for bladder cancer. Statistically significant excess risks were observed for metal workers, particularly blacksmiths, toolmakers and machine tool operators (OR: 2.0, 95% CI: 1.1-3.6), tobacco workers (OR: 3.1, 95% CI: 1.1-9.3), field crop and vegetable farm workers (OR: 1.8, 95% CI: 1.0-3.1), tailors and dress makers (OR: 1.4, 95% CI: 1.0-2.1), saleswomen (OR: 2.6, 95% CI: 1.0-6.9), and mail sorting clerks (OR: 4.4, 95% CI: 1.0-19.5). About 8% (95% CI: 3.1-19.9) of all bladder cancers in women could be attributed to occupation after adjusting for smoking. The attributable risk was higher in women aged less than 65 years (12%), compared to older women (4%). Conclusions: The calculation of the attributable risk on the basis of results from this analysis may have caused some overestimation of the proportion of occupational bladder cancer in women. A significant proportion, however, of bladder cancer cases among European women less than 65 years is likely to be attributed to occupation. This link between bladder cancer in women and occupational factors has received little recognition, probably because studies addressing these issues have predominantly been done in men.

Tobacco, occupation and non‐transitional‐cell carcinoma of the bladder: An international case‐control study

Abstract: Transitional-cell carcinoma is the dominant histological type of malignant tumors of the urinary bladder. There is limited information on risk factors for non-transitional-cell carcinoma (NTCC) of the bladder. We used data from 9 case-control studies on bladder cancer from 6 European countries to examine the association between NTCC, tobacco smoking and occupation. Information on 146 cases diagnosed with NTCC were matched by age, gender and study center to 727 non-cancer population or hospital controls and also with 722 transitional-cell-bladder-cancer controls. Lifetime smoking and occupational history were evaluated. A statistically significant excess risk for NTCC was observed for current smoking [odds ratio (OR) = 3.61, 95% confidence interval (CI) 2.08-6.28]. The risk increased with higher tobacco consumption (OR for highest tertile of pack-years = 7.01, 95% CI 3.60-13.66). The risks were higher for squamous-cell carcinomas than for other types of NTCC. Among major occupational groups, a significant excess risk was seen for field-crop and vegetable-farm workers (OR = 2.06, 95% CI 1.03-4.10). These results indicate that NTCC of the bladder is associated with smoking and specific occupations. The risk pattern seems to differ, in part, from that observed for transitional-cell carcinoma of the bladder.

Smoking as a confounder in case-control studies of occupational bladder cancer in women.

Abstract: Background: In studies in men, risk estimates on occupation and bladder cancer are distorted by about 10% when not adjusting for smoking. We examined the degree to which occupational risk estimates for bladder cancer in women are confounded by smoking, and the degree of residual confounding by inadequate control of this effect. Methods: Primary data of 11 case-control studies on occupation and bladder cancer from Denmark, France, Germany, Greece, Italy, and Spain were pooled. Information for smoking and lifetime occupational history for 700 female cases and 2,425 female controls ages 30–79 was abstracted and recoded. Logistic regression was used to calculate odds ratios (OR) by occupation, applying five models which differed in their degree of adjustment for smoking. Results: In major occupational groups, risk estimates were distorted by less than 10% when not adjusting for smoking. A statistically significant excess risk for bladder cancer was found in 13 specific occupations and industries. In most occupations, adjustment for smoking led the ORs towards the null value, but all statistically significant associations were maintained after adjustment. In three occupations (lathe operators, field crop workers, and wood manufacturers), a statistically significant excess risk was masked when not adjusting for smoking. In six occupations, estimates were distorted by more than 10% (−22% up to +40%). In occupations where smoking acted as a positive confounder, the proportion of confounding removed using a dichotomous smoking variable (ever/never) was around 60%. In one occupation (buyers), controlling for smoking status (ever, never) led to over-adjustment, because the percentage of smokers was high but the quantity smoked was low. Conclusions: Tobacco smoking was not found to be a major confounder for the association between occupation and bladder cancer in women. Most of this confounding effect could be removed by adjustment by smoking status (ever/never), without consideration of amount or duration of smoking. Am. J. Ind. Med. 36:75–82, 1999. © 1999 Wiley-Liss, Inc.